Small: Start checking URLs using PVer4. Verdict not returned to client yet.

components/safe_browsing_db/v4_feature_list.cc

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/feature_list.h"
+#include "components/safe_browsing_db/v4_feature_list.h"
+
+namespace safe_browsing {
+
+#ifdef NDEBUG

[Nathan Parker, 2016/09/28 22:25:55]

I'm wondering if we should not auto-enable this on debug -- that means the debug
build never tests the baseline functionality (w/o v4) and some of the  you're
adding in this CL.  Instead, you could rely on the chromium test .json config
that switches on the appropriate experiment/feature, and you could run your own
with the command line flag to force it enabled.  

[vakh (use Gerrit instead), 2016/09/28 23:00:01]

I agree. How about I test all that after submitting the CL and then remove the
ifdefs as a separate CL?
Reason: This CL won't be blocked by my lack of understanding of how to test
finch flags from the command line.

[Nathan Parker, 2016/09/28 23:50:14]

Sure, though the flags look simple:
https://g3doc.corp.google.com/analysis/uma/g3doc/finch/feature-api.md?cl=head

That doc describes a way to add an entry in chrome://flags -- let's do that. 
That'll make it easier to enable it in a sticky way.  I'm sure we'll run into
cases where we need to walk a walk a googler through enabling/testing pver4 on
their mac/windows/chromeos where command line flags are more annoying.

+namespace {
+const base::Feature kLocalDatabaseManagerEnabled{
+    "SafeBrowsingV4LocalDatabaseManagerEnabled",
+    base::FEATURE_DISABLED_BY_DEFAULT};
+
+const base::Feature kParallelCheckEnabled{"SafeBrowingV4ParallelCheckEnabled",
+                                          base::FEATURE_DISABLED_BY_DEFAULT};
+}  // namespace
+#endif
+
+bool V4FeatureList::IsLocalDatabaseManagerEnabled() {
+#ifndef NDEBUG
+  return true;
+#else
+  return IsV4ParallelCheckEnabled() ||
+         base::FeatureList::IsEnabled(kLocalDatabaseManagerEnabled);
+#endif
+}
+
+bool V4FeatureList::IsParallelCheckEnabled() {
+#ifndef NDEBUG
+  return true;
+#else
+  return base::FeatureList::IsEnabled(kParallelCheckEnabled);
+#endif
+}
+
+}  // namespace safe_browsing